Hydrolyzing fluorodiazadienes to form n,n&#39;-fluoroaliphatic-substituted ureas

ABSTRACT

THIS INVENTION RELATES TO A NOVEL PROCESS FOR HYDROLYZING FLUORODIAZADIENES, SUCH AS   CF2=N(CF2)NN=CF2   OR CF2=N(CFXCFY)NN=CF2, WHERE X AND Y ARE EACH FLUORINE OR A LOWER PERFLUOROALKYL GROUP, AND N REPRESENTS AN INTEGER BETWEEN 1 AND ABOUT 20, INCLUSIVE, AND TO THE NOVEL N,N&#39;&#39;-FLUOROALIPHATIC-SUBSTITUTED UREAS OF THE FORMULA   R1-((CF2)P-NH-CO-NH-(CF2)P)M-R2   WHERE R1 AND R2 ARE FLUOROALIPHATIC RADICALS, SUCH AS TRIFLUOROMETHYL, -CF3, OR R1 AND R2 TOGETHER CAN FORM PART OF A FLUOROALICYCLIC (PREFEREABLY PERFLUOROALICYCLIC) RING MADE UP OF CARBON AND NITROGEN ATOMS, PREFERABLY A IMIDAZOLIDONE RING, OR R1 AND R2 ARE TERMINAL GROUPS WHICH ARE RESIDUES OF A HYDROLYZED AZOMETHINE GROUP, P IS ZERO AND M IS 1 WHEN R1 AND R2 ARE SAID FLUOROALIPHATIC RADICALS OR TOGETHER FORM SAID FLUOROALICYCLIC RING, OR P IS AN INTEGER, PREFERABLY 2 TO 10, INCLUSIVE, AND M IS AN INTEGER OF 5 TO 100 INCLUSIVE, WHEN R1 AND R2 ARE SAID RESIDUES OF HYDROLYZED AZOMETHINE.

Unired States Patent ce 3,745,169 Patented July 10, 1973 US. Cl.260-3095 9 Claims ABSTRACT OF THE DISCLOSURE This invention relates to anovel process for hydrolyzing fluorodiazadienes, such as or CF=N(CFXCFY-),,N=CF where X and Y are each fluorine or a lowerperfluoroalkyl group, and n represents an integer between 1 and about20, inclusive, and to the novel N,N'-fluoroaliphatic-substituted ureasof the formula F, NHENH(CF L\ AJm where R and R are fluoroaliphaticradicals, such as trifiuoromethyl, C-F or R and R together can form partof a fluoroalicyclic (preferably perfluoroalicyclic) ring made up ofcarbon and nitrogen atoms, preferably a imidazolidone ring, or R and Rare terminal groups which are residues of a hydrolyzed azomethine group,p is zero and m is 1 when R and R are said fluoroaliphatic radicals ortogether form said fluoroalicyclic ring, or p is an integer, preferably2 to 10, inclusive, and m is an integer of 5 to 100 inclusive, when Rand R are said residues of hydrolyzed azomethine.

CROSS-REFERENCE This application is a continuation-in-part applicationof copending application Ser. No. 627,609, filed Apr. 13, 1967, now US.Pat. No. 3,538,157, the disclosure of which is incorporated herein byreference.

BACKGROUND [Banks, Cheng, and Haszeldine, J. Chem. Soc., 2458 (1964)];and compounds disclosed by Pearlson and Hals in US. Pat. No. 2,643,267.All of these compounds decompose in the presence of water.

Although N perfluoroalkyl substituted ureas and urethanes have beenreported [Dannley and Yamashire, J. Org. Chem., 27,599 (1962) andreferences therein], these compounds are not completely fluorinated andcontain a hydrocarbon moiety. They are prepared by the condensation of afiuoroalkyl isocyanate and either an alcohol or an amine. For instance,N-(perfluoro-n-propyl)-N'-phenylurea, C3F'1NHCONHC6H5, is prepared fromperfiuoro-npropylisocyanate C F -NCO and aniline C H NH These compoundsare unstable. They decompose spontaneously at room temperature and reactvigorously in the presence of water.

In those cases which have been reported, the result of hydrolysis of aterminal ,aihmethine containing the moiety involves initial conversionof the perfluoroazomethine group (N=CF to an isocyanate group with asubsequent hydrolysis to a nitrile, a carboxylic acid amide, or theammonium salt of a carboxylic acid. Similarly, perfiuoroazaalkenes inwhich the CF=N bond is not terminal have been reported to yieldperfiuorocarboxylic acids upon hydrolysis. As far as is known, no onehas heretofore isolated or identified perfluoro(alkylamides).

SUMMARY It has now been discovered that certain perfiuorodiazadienes canbe controllably hydrolyzed to produce a new class of compounds, namelyN, N'-fluoroaliphatic substituted ureas, which are represented by thegeneral formula F I? 'I R]|:(CFg) NHCNH(C 2)DIR2 where R and R arefluoroaliphatic radicals, such as trifluoromethyl, -CF or R and Rtogether can form part of a fluoroalicyclic (preferablyperfluoroalicyclic) ring made up of carbon and nitrogen atoms,preferably imidazolidone ring, or R and R are terminal groups which areresidues of a hydrolyzed azomethine group, p is zero and m is 1 when Rand R are said fluoroaliphatic radicals or together form saidfluoroalicyclic ring, or p is an integer, preferably 2 to 10, inclusive,and m is an integer of 5 to 100, inclusive, when R and R are saidresidues of hydrolyzed azomethine.

The above general formula covers three subclasses of compounds, whichare represented by the formulas where R, is a fluoroaliphatic radical,such as trifiuoromethyl, CF X and Y are fluorine or lower prefiuoroalkylradicals, e.g., --CF A is a residue from the hydrolysis of a terminalazomethine group, n is an integer of 4 to 20, inclusive, and m is aninteger of 5 to 100, inclusive.

The fluoroaliphatic radical, R is a fluorinated aliphatic radicalcontaining at least one carbon atom in the skeletal chain. The chain maybe straight, branched, or cyclic, and may be interrupted by divalentoxygen atoms or divalent sulphur atoms. Preferably, such skeletal chaindoes not contain more than one oxygen or sulphur atom for every twocarbon atoms in the skeletal chain. It is preferred to have onlyfluorine present as substituents to satisfy non-skeletal valences.Preferably, such fluoroaliphatic radical contains less than about 20carbon atoms in its skeletal chain. More preferably, R; is a lowerperthe dangling valences of each such moiety each being satisfied by amember of the group consisting of fluorine,

chlorine, perfluoroalkyl, perfluoroalkylene, perfluorochloroalkylene,and percuoro-azaalkylene. Preferably, such starting perfluorodiazadienescontain less than thirty carbon atoms each. Preferred classes ofperfiuorodiazadiene starting materials are characterized by thefollowing generic formulas:

where X and Y are each fluorine or a lower perfluoro alkyl group, 20 andn represents an integer between 1 and about 20, inclusive.

The compounds of Formulas 4 and 5 may be prepared by the ultravioletphotolysis of perfluoro-2,3-diazabuta- 1,3-diene and either afluorinated olefin or a source of perfluorinated carbene, such asdifluorocarbene (copending U.S. patent application Ser. No. 562,540, nowU.S. Pat. 3,584,048.

The controlled hydrolysis of the starting compounds of Formulas 4 and 5,in accordance with the present invention, is carried out by maintainingsuch compounds in contact with stoichiometric or excess amounts of waterfor a length of time which is sufficient to convert substantially all ofthe azomethine groups thereof into perfluoro (alkylamide) groups asillustrated by the following Equations I and II:

where X is as defined above, n is as defined above, m represents aninteger from about 5 through 100, and A is a terminal group which is ahydrolysis residue from the terminal azomethine groups, for example, Ais a carboxyl or amide. In some instances, such as when X and Y arefluoride, compounds of the formula may be formed in situ duringhydrolysis of the compounds of Formulas 4 and 5, thence producingperfluoro (alkylamides), as illustrated by Equation II where n is morethan two:

Although such hydrolyses can be carried out in basic environment, thatis, an environment wherein the pH is greater than 7 (i.e. which is notstrongly basic), the yield of N,N'-fluoroaliphatic product is reduced insuch instances, presumably due to decomposition, as, for example, byfurther hydrolysis of products. Therefore, a pH of about 7 or below ispreferred in practicing the hydrolysis teachings of this invention.While the hydrolysis reaction can be carried out with the diazadienestarting material present primarily in the gas phase, it is pre- 4ferred to use the liquid phase, and it is more preferred to use anorganic mutual solvent in which both water and starting diazodiene aresoluble. Such mutual solvent should be inert towards the diazadiene,i.e., it should be free of reactive groups such as active hydrogen, andfree of hydrolyzable groups such as esters, acyl halides, and the like.Suitable solvents include ketones, such as acetone or methyl ethylketone. Since the products of this invention are characteristicallystable to acid or neutral hydrolysis, excess water may be used.

While preferred temperatures range from about 5 to C., it will beappreciated that the exact reaction temperature used in any givensituation is not critical. Thus, for example, lower temperatures may beused with longer reaction times.

The hydrolysis reaction can be conveniently monitored by examining theinfrared spectra of the volatile materials since theN,N'-fiuoroaliphatic-substituted urea products of this invention aresolids of low vapor pressure at room temperature. Solvents and startingmaterials, which are volatile, may be removed by evaporation. Thedesired products may be separated by crystallization or sublimation.

Depending upon selection of starting material, one obtains differentproducts which are either cyclic or acyclic.

When the compound of Formula 4 in which n=1 is hydrolyzed in accordancewith the invention, there is produced a compound of the formula:

The compound of Formula 6 is N,N'-bis(trifiuoromethyl)urea which alsocan be termed perfluoro (N,N'-dimethylurea). This compound is a whitesolid which sublimes at 100 C. under atmospheric pressure, and issoluble in common organic solvents such as acetone and ethanol.

CF NHCONHCF The compound of Formula 6 is useful as a nuclear mag neticresonance spectral reference compound because it produces a well-definedF doublet in polar solvents such as acetone. This compound also displaysherbical activity, especially against green foxtail grass.

When compounds of Formula 4 in which n is greater than three arehydrolyzed by water under acid or neutral conditions there are producedN,N-perfluoroalkylenesubstituted ureas which are polymeric and can becharacterizable by the following formula:

When a compound of Formula 5 is hydrolyzed in accordance with thisinvention, there is produced a compound characterized by the genericformula:

H1 I'm 5 wherein X and Y are each as defined above.

These compounds of Formula 8 are N,N'-perfluoroalkylene-substitutedureas which can be termed 4,5-perfluoro-substituted-Z-imidazolidones.Preferred compounds of Formula 8 are those where X is fluorine and Y isa lower perfluoroal-kyl radical- Formula 8 compounds arecharacteristically white solids soluble in common organic solvents, suchas acetone and slightly soluble in water. These compounds arecharacteristically thermally and hydrolytically stable under ambientconditions. They are characteristically recovered unchanged aftersublimation.

The compounds of Formula 8 are useful as clothtreating agents since whendeposited on cloth they impart water-repelling properties to clothfibers containing reactive hydrogen atoms, such as, cellulose (cotton)fibers or protein (wool) fibers.

The invention is illustrated in greater detail by the followingexamples. In all cases, the products described are purified either bycrystallization from acetone or by sublimation or by both.

Example 1 Perfluoro-2,4 -diazapenta-1,4-diene,

OFg,

(0.5 g.) is condensed under vacuum at 196 C. into a Pyrex glass bulbwhich contains 5 cc. of water. After warming to room temperature, thebulb and its contents are allowed to stand for 24 hours. The white solidwhich deposits is then filtered off, washed with a small quantity ofwater, and after purification is identified by its elemental analysis asperfluoro(N,N'-dimethylurea),

The yield is approximately 0.2 g. (-40%).

Analysis.-Calcd. for caHg'FgNgo (percent): C, 18.4; H, 1.0; N, 14.8.Found (percent): C, 19.0; H, 1.2; N, 14.3. The structure of the productis confirmed by its F n.m.r. spectrum which contains a doublet (J=3.3cps.) at 56.2 41* [see G. Filipovich and G. V. D. Tiers, J. Phys. Chem.,63, 761 (1959)] and its infrared spectrum which shows absorptions at3.01.1.4 and 6.2a corresponding to the NH bonds and 5.89 4 correspondingto the carbonyl bond.

Example 2 The process of Example 1 is repeated using perfluoro-2,5-diazahexa1-1,5-diene, CFg=NCFzCF -N=CFPer'fluoro(N,N'-dimethyloxamide) (approximately 20% of theoretical) isobtained together with a small quantity of a solid which is appreciablymore soluble in water. This solid is identified by its F n.m.r. andinfrared spectrum as perfluoro-2-imidazolidone,

CF1-(|] F: NE NH Its -F n.m.r. spectrum shows a signal at 94corresponding to CFgand its infrared spectrum shows absorptions at 3.1aand 5.7,u corresponding to the NH bonds and carbonyl bond, respectively.

Example 3 The process of Example 1 is repeated using perfluoro-(3-methyl-2,5-diazahexa-1,5-diene),

6 After purification, the white solid product is identified by itselemental analysis as perfl'uoro(4-methyl-2-imidazolidone),

0 F30 F-C F,

HN NH The yield is about 40% theory.

Analysis.-Calcd. for C H F N O (percent): C, 23.1; H, 1.0; N, 13.5.Found (percent): C, 23.1;H, 1.0; N, 12.8.

The structure of the product is confirmed byits F n.m.r. spectrum whichshows a complex doublet (J= 13.9 cps.) at 79.3 corresponding to the CF;,group, a complex peak at 134.8 corresponding to the CF group, and an ABpattern (1:188 cps.) at 84.6 and 91.3 corresponding to the CF group, andby its infrared spectrum which shows absorptions at 3.09; and 3.1corresponding to the NH bonds and at 5.65; corresponding to the carbonylbond.

Example 4 Perfluoro-2,3-diazabuta-1,3-diene (1 part) andtetrafluoroethylene (10 parts) are photolyzed together for 5 hours in asilica tube using a BH-6 lamp, at room temperature. A white solid isproduced which is shown by its infrared spectrum to have thecharacteristic structure where the value of n is about 20. This materialis then hydrolyzed with water to produce a white, insoluble highmeltingsolid which is identified as a polyperfluorourea by its infraredspectrum. The terminal groups of this polymer are advantageoushydrolysis products of terminal azomethine groups of terminalmethylimino groups. After prolonged heating with 40% alcoholic sodiumhydroxide solution, this material is converted into the sodium salt of ahigh-molecular weight fluorinated carboxylic acid which is identified assuch by its characteristic infrared spectrum.

I claim:

1. A process comprising contacting and hydrolyzing aperfluorobisazomethine with water having a pH not substantially above 7,and recovering the resulting N,N'- substituted urea, saidperfluorobisazomethine having the formula 4. The process of claim 1wherein said perfluorobisazomethine has said Formula II, X is fluorine,Y is CF;,, and n is 1.

5. A compound having the formula CF NHCONHCF 6. Compounds of the formulawhere X and Y are fluorine or lower perfluoroalkyl.

7. A compound of claim 6 wherein X is fluorine and Y is trifluoromethyl.

7 8 8. Compounds of the formula n is an integer of 4 to 20, and m is aninteger of 5 to 100. RPLCFQDNHgNHwMDlR, References Cited L m UNITEDSTATES PATENTS wherein R and R are either fluoroaliphatic radicals or 52,656,334 10/1953 Lindgren at 260 553 R together form a fiuoroalicyclicring when p is zero and m 3,433,800 3/1969 Parker is 1, or wherein R andR are carboxyl, amide, isocyanate, or ntitrile ggosutps lwgen p is aninteger of 2 to 10 and DONALD E CZAJA, p i Examiner misanmegero o 9.Perfluoropolyureas of the formula 10 WELSH Asslstant Exammer US. Cl.X.R.

where A is carboxyl, amide, isocyanato, or nitrile group, 15

Patent No. 3 1H5 169 and that said Letters Patent :1

EDWARD M.FLETCHER, JR. Attesting Officer UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Dated JulylO. 1973 Inventor(s) PAUL Hi OGDENat error appears in the above-identified patent It is certified th rehereby corrected as shown below:

Column 3, Line 3,

"fluoroidazadienes" should read fluorodiazadienes K Column 3, Line 21,"20" should be deleted Column 5, Line 55 "diazahexal" should r-eaddiazahexa Column 6, Line 35, "advantageous" should read adventitiousSigned and sealed. this 27th day of November 1973.

(SEAL) Attest:

RENE D. TEGTMEYER Acting Commissioner of Patents FORM PO-IOSQ (IO-69)

